Lands http://codereview.chromium.org/7262024/ for Ian:

Added interpolated transforms

BUG= none
TEST=ui_unittests

Review URL: http://codereview.chromium.org/7285003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@91145 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 529 insertions, 0 deletions

diff --git a/ui/gfx/interpolated_transform.cc b/ui/gfx/interpolated_transform.cc
new file mode 100644
index 0000000..1f37f84
--- /dev/null
+++ b/ui/gfx/interpolated_transform.cc
@@ -0,0 +1,219 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/gfx/interpolated_transform.h"
+
+#include "base/logging.h"
+#include "ui/base/animation/tween.h"
+
+namespace ui {
+
+///////////////////////////////////////////////////////////////////////////////
+// InterpolatedTransform
+//
+
+InterpolatedTransform::InterpolatedTransform()
+    : start_time_(0.0f),
+      end_time_(1.0f) {
+}
+
+InterpolatedTransform::InterpolatedTransform(float start_time,
+                                             float end_time)
+    : start_time_(start_time),
+      end_time_(end_time) {
+}
+
+InterpolatedTransform::~InterpolatedTransform() {}
+
+ui::Transform InterpolatedTransform::Interpolate(float t) const {
+  ui::Transform result = InterpolateButDoNotCompose(t);
+  if (child_.get()) {
+    result.ConcatTransform(child_->Interpolate(t));
+  }
+  return result;
+}
+
+void InterpolatedTransform::SetChild(InterpolatedTransform* child) {
+  child_.reset(child);
+}
+
+inline float InterpolatedTransform::ValueBetween(float time,
+                                                 float start_value,
+                                                 float end_value) const {
+  // can't handle NaN
+  DCHECK(time == time && start_time_ == start_time_ && end_time_ == end_time_);
+  if (time != time || start_time_ != start_time_ || end_time_ != end_time_)
+    return start_value;
+
+  // Ok if equal -- we'll get a step function. Note: if end_time_ ==
+  // start_time_ == x, then if none of the numbers are NaN, then it
+  // must be true that time < x or time >= x, so we will return early
+  // due to one of the following if statements.
+  DCHECK(end_time_ >= start_time_);
+
+  if (time < start_time_)
+    return start_value;
+
+  if (time >= end_time_)
+    return end_value;
+
+  float t = (time - start_time_) / (end_time_ - start_time_);
+  return static_cast<float>(Tween::ValueBetween(t, start_value, end_value));
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// InterpolatedRotation
+//
+
+InterpolatedRotation::InterpolatedRotation(float start_degrees,
+                                           float end_degrees)
+    : InterpolatedTransform(),
+      start_degrees_(start_degrees),
+      end_degrees_(end_degrees) {
+}
+
+InterpolatedRotation::InterpolatedRotation(float start_degrees,
+                                           float end_degrees,
+                                           float start_time,
+                                           float end_time)
+    : InterpolatedTransform(start_time, end_time),
+      start_degrees_(start_degrees),
+      end_degrees_(end_degrees) {
+}
+
+InterpolatedRotation::~InterpolatedRotation() {}
+
+ui::Transform InterpolatedRotation::InterpolateButDoNotCompose(float t) const {
+  ui::Transform result;
+  result.SetRotate(ValueBetween(t, start_degrees_, end_degrees_));
+  return result;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// InterpolatedScale
+//
+
+InterpolatedScale::InterpolatedScale(float start_scale,
+                                     float end_scale)
+    : InterpolatedTransform(),
+      start_scale_(start_scale),
+      end_scale_(end_scale) {
+}
+
+InterpolatedScale::InterpolatedScale(float start_scale,
+                                     float end_scale,
+                                     float start_time,
+                                     float end_time)
+    : InterpolatedTransform(start_time, end_time),
+      start_scale_(start_scale),
+      end_scale_(end_scale) {
+}
+
+InterpolatedScale::~InterpolatedScale() {}
+
+ui::Transform InterpolatedScale::InterpolateButDoNotCompose(float t) const {
+  ui::Transform result;
+  float interpolated_scale = ValueBetween(t, start_scale_, end_scale_);
+  // TODO(vollick) 3d xforms.
+  result.SetScale(interpolated_scale, interpolated_scale);
+  return result;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// InterpolatedTranslation
+//
+
+InterpolatedTranslation::InterpolatedTranslation(const gfx::Point& start_pos,
+                                                 const gfx::Point& end_pos)
+    : InterpolatedTransform(),
+      start_pos_(start_pos),
+      end_pos_(end_pos) {
+}
+
+InterpolatedTranslation::InterpolatedTranslation(const gfx::Point& start_pos,
+                                                 const gfx::Point& end_pos,
+                                                 float start_time,
+                                                 float end_time)
+    : InterpolatedTransform(start_time, end_time),
+      start_pos_(start_pos),
+      end_pos_(end_pos) {
+}
+
+InterpolatedTranslation::~InterpolatedTranslation() {}
+
+ui::Transform
+InterpolatedTranslation::InterpolateButDoNotCompose(float t) const {
+  ui::Transform result;
+  // TODO(vollick) 3d xforms.
+  result.SetTranslate(ValueBetween(t, start_pos_.x(), end_pos_.x()),
+                      ValueBetween(t, start_pos_.y(), end_pos_.y()));
+
+  return result;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// InterpolatedConstantTransform
+//
+
+InterpolatedConstantTransform::InterpolatedConstantTransform(
+  const ui::Transform& transform)
+    : InterpolatedTransform(),
+  transform_(transform) {
+}
+
+ui::Transform
+InterpolatedConstantTransform::InterpolateButDoNotCompose(float t) const {
+  return transform_;
+}
+
+InterpolatedConstantTransform::~InterpolatedConstantTransform() {}
+
+///////////////////////////////////////////////////////////////////////////////
+// InterpolatedTransformAboutPivot
+//
+
+InterpolatedTransformAboutPivot::InterpolatedTransformAboutPivot(
+  const gfx::Point& pivot,
+  InterpolatedTransform* transform)
+    : InterpolatedTransform() {
+  Init(pivot, transform);
+}
+
+InterpolatedTransformAboutPivot::InterpolatedTransformAboutPivot(
+  const gfx::Point& pivot,
+  InterpolatedTransform* transform,
+  float start_time,
+  float end_time)
+    : InterpolatedTransform() {
+  Init(pivot, transform);
+}
+
+InterpolatedTransformAboutPivot::~InterpolatedTransformAboutPivot() {}
+
+ui::Transform
+InterpolatedTransformAboutPivot::InterpolateButDoNotCompose(float t) const {
+  if (transform_.get()) {
+    return transform_->Interpolate(t);
+  }
+  return ui::Transform();
+}
+
+void InterpolatedTransformAboutPivot::Init(const gfx::Point& pivot,
+                                           InterpolatedTransform* xform) {
+  ui::Transform to_pivot;
+  ui::Transform from_pivot;
+  to_pivot.SetTranslate(-pivot.x(), -pivot.y());
+  from_pivot.SetTranslate(pivot.x(), pivot.y());
+
+  scoped_ptr<InterpolatedTransform> pre_transform(
+    new InterpolatedConstantTransform(to_pivot));
+  scoped_ptr<InterpolatedTransform> post_transform(
+    new InterpolatedConstantTransform(from_pivot));
+
+  pre_transform->SetChild(xform);
+  xform->SetChild(post_transform.release());
+  transform_.reset(pre_transform.release());
+}
+
+} // namespace ui
diff --git a/ui/gfx/interpolated_transform.h b/ui/gfx/interpolated_transform.h
new file mode 100644
index 0000000..2a0a6b5
--- /dev/null
+++ b/ui/gfx/interpolated_transform.h
@@ -0,0 +1,195 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UI_GFX_INTERPOLATED_TRANSFORM_H_
+#define UI_GFX_INTERPOLATED_TRANSFORM_H_
+#pragma once
+
+#include "ui/gfx/transform.h"
+#include "base/memory/scoped_ptr.h"
+#include "ui/gfx/point.h"
+
+namespace ui {
+
+///////////////////////////////////////////////////////////////////////////////
+// class InterpolatedTransform
+//
+// Abstract base class for transforms that animate over time. These
+// interpolated transforms can be combined to allow for more sophisticated
+// animations. For example, you might combine a rotation of 90 degrees between
+// times 0 and 1, with a scale from 1 to 0.3 between times 0 and 0.25 and a
+// scale from 0.3 to 1 from between times 0.75 and 1.
+//
+///////////////////////////////////////////////////////////////////////////////
+class InterpolatedTransform {
+ public:
+  InterpolatedTransform();
+  // The interpolated transform varies only when t in (start_time, end_time).
+  // If t <= start_time, Interpolate(t) will return the initial transform, and
+  // if t >= end_time, Interpolate(t) will return the final transform.
+  InterpolatedTransform(float start_time, float end_time);
+  virtual ~InterpolatedTransform();
+
+  // Returns the interpolated transform at time t. Note: not virtual.
+  ui::Transform Interpolate(float t) const;
+
+  // The Intepolate ultimately returns the product of our transform at time t
+  // and our child's transform at time t (if we have one).
+  //
+  // This function takes ownership of the passed InterpolatedTransform.
+  void SetChild(InterpolatedTransform* child);
+
+ protected:
+  // Calculates the interpolated transform without considering our child.
+  virtual ui::Transform InterpolateButDoNotCompose(float t) const = 0;
+
+  // If time in (start_time_, end_time_], this function linearly interpolates
+  // between start_value and end_value.  More precisely it returns
+  // (1 - t) * start_value + t * end_value where
+  // t = (start_time_ - time) / (end_time_ - start_time_).
+  // If time < start_time_ it returns start_value, and if time >= end_time_
+  // it returns end_value.
+  float ValueBetween(float time, float start_value, float end_value) const;
+
+ private:
+  const float start_time_;
+  const float end_time_;
+
+  // The child transform. If you consider an interpolated transform as a
+  // function of t. If, without a child, we are f(t), and our child is
+  // g(t), then with a child we become f'(t) = f(t) * g(t). Using a child
+  // transform, we can chain collections of transforms together.
+  scoped_ptr<InterpolatedTransform> child_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterpolatedTransform);
+};
+
+///////////////////////////////////////////////////////////////////////////////
+// class InterpolatedRotation
+//
+// Represents an animated rotation.
+//
+///////////////////////////////////////////////////////////////////////////////
+class InterpolatedRotation : public InterpolatedTransform {
+ public:
+  InterpolatedRotation(float start_degrees, float end_degrees);
+  InterpolatedRotation(float start_degrees,
+                       float end_degrees,
+                       float start_time,
+                       float end_time);
+  virtual ~InterpolatedRotation();
+
+ protected:
+  virtual ui::Transform InterpolateButDoNotCompose(float t) const OVERRIDE;
+
+ private:
+  const float start_degrees_;
+  const float end_degrees_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterpolatedRotation);
+};
+
+///////////////////////////////////////////////////////////////////////////////
+// class InterpolatedScale
+//
+// Represents an animated scale.
+//
+///////////////////////////////////////////////////////////////////////////////
+class InterpolatedScale : public InterpolatedTransform {
+ public:
+  InterpolatedScale(float start_scale, float end_scale);
+  InterpolatedScale(float start_scale,
+                    float end_scale,
+                    float start_time,
+                    float end_time);
+  virtual ~InterpolatedScale();
+
+ protected:
+  virtual ui::Transform InterpolateButDoNotCompose(float t) const OVERRIDE;
+
+ private:
+  const float start_scale_;
+  const float end_scale_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterpolatedScale);
+};
+
+class InterpolatedTranslation : public InterpolatedTransform {
+ public:
+  InterpolatedTranslation(const gfx::Point& start_pos,
+                          const gfx::Point& end_pos);
+  InterpolatedTranslation(const gfx::Point& start_pos,
+                          const gfx::Point& end_pos,
+                          float start_time,
+                          float end_time);
+  virtual ~InterpolatedTranslation();
+
+ protected:
+  virtual ui::Transform InterpolateButDoNotCompose(float t) const OVERRIDE;
+
+ private:
+  const gfx::Point start_pos_;
+  const gfx::Point end_pos_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterpolatedTranslation);
+};
+
+///////////////////////////////////////////////////////////////////////////////
+// class InterpolatedConstantTransform
+//
+// Represents a transform that is constant over time. This is only useful when
+// composed with other interpolated transforms.
+//
+// See InterpolatedTransformAboutPivot for an example of its usage.
+//
+///////////////////////////////////////////////////////////////////////////////
+class InterpolatedConstantTransform : public InterpolatedTransform {
+ public:
+  InterpolatedConstantTransform(const ui::Transform& transform);
+  virtual ~InterpolatedConstantTransform();
+
+ protected:
+  virtual ui::Transform InterpolateButDoNotCompose(float t) const OVERRIDE;
+
+ private:
+  const ui::Transform transform_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterpolatedConstantTransform);
+};
+
+///////////////////////////////////////////////////////////////////////////////
+// class InterpolatedTransformAboutPivot
+//
+// Represents an animated transform with a transformed origin. Essentially,
+// at each time, t, the interpolated transform is created by composing
+// P * T * P^-1 where P is a constant transform to the new origin.
+//
+///////////////////////////////////////////////////////////////////////////////
+class InterpolatedTransformAboutPivot : public InterpolatedTransform {
+ public:
+  // Takes ownership of the passed transform.
+  InterpolatedTransformAboutPivot(const gfx::Point& pivot,
+                                  InterpolatedTransform* transform);
+
+  // Takes ownership of the passed transform.
+  InterpolatedTransformAboutPivot(const gfx::Point& pivot,
+                                  InterpolatedTransform* transform,
+                                  float start_time,
+                                  float end_time);
+  virtual ~InterpolatedTransformAboutPivot();
+
+ protected:
+  virtual ui::Transform InterpolateButDoNotCompose(float t) const OVERRIDE;
+
+ private:
+  void Init(const gfx::Point& pivot, InterpolatedTransform* transform);
+
+  scoped_ptr<InterpolatedTransform> transform_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterpolatedTransformAboutPivot);
+};
+
+} // namespace ui
+
+#endif // UI_GFX_INTERPOLATED_TRANSFORM_H_
diff --git a/ui/gfx/interpolated_transform_unittest.cc b/ui/gfx/interpolated_transform_unittest.cc
new file mode 100644
index 0000000..1aff853
--- /dev/null
+++ b/ui/gfx/interpolated_transform_unittest.cc
@@ -0,0 +1,112 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/gfx/interpolated_transform.h"
+
+#include "base/basictypes.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+const static float EPSILON = 1e-6f;
+
+bool ApproximatelyEqual(float lhs, float rhs) {
+  if (lhs == 0)
+    return fabs(rhs) < EPSILON;
+  if (rhs == 0)
+    return fabs(lhs) < EPSILON;
+  return fabs(lhs - rhs) / std::max(fabs(rhs), fabs(lhs)) < EPSILON;
+}
+
+bool ApproximatelyEqual(const ui::Transform& lhs, const ui::Transform& rhs) {
+  for (int i = 0; i < 9; ++i) {
+    if (!ApproximatelyEqual(lhs.matrix()[i], rhs.matrix()[i]))
+      return false;
+  }
+  return true;
+}
+
+} // namespace
+
+TEST(InterpolatedTransformTest, InterpolatedRotation) {
+  ui::InterpolatedRotation interpolated_rotation(0, 100);
+  ui::InterpolatedRotation interpolated_rotation_diff_start_end(
+      0, 100, 100, 200);
+
+  for (int i = 0; i <= 100; ++i) {
+    ui::Transform rotation;
+    rotation.SetRotate(i);
+    ui::Transform interpolated = interpolated_rotation.Interpolate(i / 100.0f);
+    EXPECT_TRUE(ApproximatelyEqual(rotation, interpolated));
+    interpolated = interpolated_rotation_diff_start_end.Interpolate(i + 100);
+    EXPECT_TRUE(ApproximatelyEqual(rotation, interpolated));
+  }
+}
+
+TEST(InterpolatedTransformTest, InterpolatedScale) {
+  ui::InterpolatedScale interpolated_scale(0, 100);
+  ui::InterpolatedScale interpolated_scale_diff_start_end(
+      0, 100, 100, 200);
+
+  for (int i = 0; i <= 100; ++i) {
+    ui::Transform scale;
+    scale.SetScale(i, i);
+    ui::Transform interpolated = interpolated_scale.Interpolate(i / 100.0f);
+    EXPECT_TRUE(ApproximatelyEqual(scale, interpolated));
+    interpolated = interpolated_scale_diff_start_end.Interpolate(i + 100);
+    EXPECT_TRUE(ApproximatelyEqual(scale, interpolated));
+  }
+}
+
+TEST(InterpolatedTransformTest, InterpolatedTranslate) {
+  ui::InterpolatedTranslation interpolated_xform(gfx::Point(0, 0),
+                                                 gfx::Point(100, 100));
+
+  ui::InterpolatedTranslation interpolated_xform_diff_start_end(
+      gfx::Point(0, 0), gfx::Point(100, 100), 100, 200);
+
+  for (int i = 0; i <= 100; ++i) {
+    ui::Transform xform;
+    xform.SetTranslate(i, i);
+    ui::Transform interpolated = interpolated_xform.Interpolate(i / 100.0f);
+    EXPECT_TRUE(ApproximatelyEqual(xform, interpolated));
+    interpolated = interpolated_xform_diff_start_end.Interpolate(i + 100);
+    EXPECT_TRUE(ApproximatelyEqual(xform, interpolated));
+  }
+}
+
+TEST(InterpolatedTransformTest, InterpolatedRotationAboutPivot) {
+  gfx::Point pivot(100, 100);
+  gfx::Point above_pivot(100, 200);
+  ui::InterpolatedRotation rot(0, 90);
+  ui::InterpolatedTransformAboutPivot interpolated_xform(
+      pivot,
+      new ui::InterpolatedRotation(0, 90));
+  ui::Transform result = interpolated_xform.Interpolate(0.0f);
+  EXPECT_TRUE(ApproximatelyEqual(ui::Transform(), result));
+  result = interpolated_xform.Interpolate(1.0f);
+  gfx::Point expected_result = pivot;
+  EXPECT_TRUE(result.TransformPoint(&pivot));
+  EXPECT_EQ(expected_result, pivot);
+  expected_result = gfx::Point(0, 100);
+  EXPECT_TRUE(result.TransformPoint(&above_pivot));
+  EXPECT_EQ(expected_result, above_pivot);
+}
+
+TEST(InterpolatedTransformTest, InterpolatedScaleAboutPivot) {
+  gfx::Point pivot(100, 100);
+  gfx::Point above_pivot(100, 200);
+  ui::InterpolatedTransformAboutPivot interpolated_xform(
+      pivot,
+      new ui::InterpolatedScale(1, 2));
+  ui::Transform result = interpolated_xform.Interpolate(0.0f);
+  EXPECT_TRUE(ApproximatelyEqual(ui::Transform(), result));
+  result = interpolated_xform.Interpolate(1.0f);
+  gfx::Point expected_result = pivot;
+  EXPECT_TRUE(result.TransformPoint(&pivot));
+  EXPECT_EQ(expected_result, pivot);
+  expected_result = gfx::Point(100, 300);
+  EXPECT_TRUE(result.TransformPoint(&above_pivot));
+  EXPECT_EQ(expected_result, above_pivot);
+}
diff --git a/ui/ui_gfx.gypi b/ui/ui_gfx.gypi
index c9907c3..2d33805bf 100644
--- a/ui/ui_gfx.gypi
+++ b/ui/ui_gfx.gypi
@@ -81,6 +81,8 @@
         'gfx/image/image_util.h',
         'gfx/insets.cc',
         'gfx/insets.h',
+        'gfx/interpolated_transform.h',
+        'gfx/interpolated_transform.cc',
         'gfx/mac/nsimage_cache.h',
         'gfx/mac/nsimage_cache.mm',
         'gfx/mac/scoped_ns_disable_screen_updates.h',
diff --git a/ui/ui_unittests.gypi b/ui/ui_unittests.gypi
index 8ea6cb2..3fb1c4a 100644
--- a/ui/ui_unittests.gypi
+++ b/ui/ui_unittests.gypi
@@ -46,6 +46,7 @@
         'gfx/image/image_unittest_util.h',
         'gfx/image/image_unittest_util.cc',
         'gfx/insets_unittest.cc',
+        'gfx/interpolated_transform_unittest.cc',
         'gfx/rect_unittest.cc',
         'gfx/run_all_unittests.cc',
         'gfx/skbitmap_operations_unittest.cc',